js.transaction.TransactionContext Maven / Gradle / Ivy
package js.transaction;
/**
* Transaction context provides access to currently executing session on transactional resource. Transaction context is designed
* to work only with transactional container and the only means to obtain it is via dependency injection.
*
* A transactional resource offers two kinds of APIs: transaction API exposes by {@link Transaction} implementation and worker
* API exposed by session instance, executed inside boundaries specified by transaction API. Worker API is used to actually
* fulfill the working unit.
*
* In sample code below, transaction context is injected into a DAO implementation and facilitate access to currently executing
* session. Session on its turn is used to perform the actual transactional working unit.
*
*
* class DaoImpl implements Dao
* {
* {@literal @}DependencyInjection
* private TransactionContext context;
* ...
* User getUser(int userId) {
* Session session = context.getSession();
* Query query = session.createQuery(...);
* ...
* }
* }
*
*
* In this context, the term session is used in a broader sense. There are implementations naming it indeed
* session or, for example JDBC, uses connection.
*
* @author Iulian Rotaru
* @version final
*/
public interface TransactionContext {
/**
* Get currently executing session on transactional resource. Session exposes transactional resource API used to fulfill
* transactional working unit.
*
* Session type depends on implementation, e.g. on Hibernate is named indeed session while on JDBC is
* connection.
*
* @return currently executing session.
* @param auto-cast to session type.
*/
T getSession();
}